Abaixo está uma instrução que descreve uma tarefa de geração de SQL, combinada com uma entrada que fornece mais contexto sobre os esquemas de tabela disponíveis. Escreva o código SQL que responda adequadamente à solicitação
 ###Instrução: Qual classificação jovem tem um piloto agressivo de Tim Johnson?
 ###Tabelas: CREATE TABLE singles:_21_10_titles_11_runners-up (singles:_21_10_titles_11_runners-up_id AUTO_INCREMENT PRIMARY KEY, Result VARCHAR, No. INT, Date VARCHAR, Category VARCHAR, Tournament VARCHAR, Surface VARCHAR, Opponent VARCHAR, Score VARCHAR) CREATE TABLE olympians (olympians_id AUTO_INCREMENT PRIMARY KEY, Last VARCHAR, First VARCHAR, Year INT, Sport VARCHAR, Country VARCHAR) CREATE TABLE compounds_from_marine_sources_in_clinical_level (compounds_from_marine_sources_in_clinical_level_id AUTO_INCREMENT PRIMARY KEY, Clinical Status VARCHAR, Compound Name VARCHAR, Trademark VARCHAR, Marine Organism α VARCHAR, Chemical Class VARCHAR, Molecular Target VARCHAR, Clinical Trials β VARCHAR, Disease Area VARCHAR) CREATE TABLE jersey_progress (jersey_progress_id AUTO_INCREMENT PRIMARY KEY, Stage (Winner) VARCHAR, General Classification VARCHAR, Young Classification VARCHAR, Sprint Classification VARCHAR, Aggressive Rider VARCHAR, Team Classification VARCHAR) CREATE TABLE florida_counties_ranked_by_per_capita_income (florida_counties_ranked_by_per_capita_income_id AUTO_INCREMENT PRIMARY KEY, County VARCHAR, Per capita income VARCHAR, Median household income VARCHAR, Median family income VARCHAR, Population INT, Number of households INT)  
SELECT Young Classification FROM jersey_progress WHERE Aggressive Rider = tim johnson